This invention relates to a telephone accessory, and particularly to one that enables individuals wearing hearing aids to conveniently use a conventional telephone.
Hearing impaired individuals are frequently able to obtain near-normal hearing through the use of hearing aids which amplify sounds. Numerous types of hearing aids are known, but the type in most prevalent use today are the so-called "in-ear" types, which resemble an ear plug inserted into the ear canal and are small and inconspicuous. Modern hearing aids contain a microphone and internally disposed battery and amplification circuits and have a sound emitter within the ear canal. Although these devices generally operate satisfactorily for normal hearing conditions, users of such hearing aids often encounter difficulty when using conventional telephones. When the telephone earpiece is brought close to the hearing aid, a high pitched squealing sound is generated due to feedback. This effect can be demonstrated by putting a sound reflective surface close to the wearer's ears. Feedback occurs since the output of the hearing aid emitter becomes closely coupled with its microphone when the hard surface such as a telephone earpiece reflects sound from the emitter back to the microphone. Due to the presence of such feedback, many users of hearing aids must use a dedicated telephone amplifying device rather than their hearing aid. The requirement for an amplified telephone is an inconvenience and is an additional expense.
In accordance with the present invention, an add-on accessory device is provided for a telephone earpiece which is inexpensive and has no moving parts and enables a conventional telephone to be used in the normal manner by a hearing impaired individual wearing a hearing aid. The devices according to the invention provide a deep cup which is attached to the telephone earpiece and directs the emitted sound to the user's ear but does not present a flat sound reflective surface in close proximity to the hearing aid. Accordingly, with the add-on accessory device in place, a conventional telephone can be used without feedback. Various embodiments of such accessory devices are described herein which include various means for attaching the device to a telephone, and includes embodiments which are readily adaptable to various users by enabling the depth of the cup to be adjusted.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.